The present invention relates to a new and distinct cultivar of Nepeta named ‘Purrsian Blue’. The new plant resulted from a cross between Nepeta ‘Six Hills Giant’ (not patented) (female or seed parent) and an unknown selection named only as ‘Eldean’ (non-patented) (male or pollen parent) hybridized by Kevin A. Hurd in the summer of 2009, seed harvested Oct. 26, 2009 and originally given the breeder code K0-19-01. ‘Purrsian Blue’ was approved in a final evaluation in the summer of 2011 and slated for later introduction. The new plant was selected based on the long blooming and compact traits. The new plant has been asexually propagated in a nursery in Zeeland, Mich. by tip cuttings with the resultant plants remaining identical to the original plant, stable and true to type in successive generations.